The separation, extraction, and purification of alumina from ores, followed by the production of aluminum. Aluminum is the most abundant metallic element on the Earth and Moon but is never found free in nature. It makes up more than 8% of the solid portion of the Earth's surface. Seawater contains an average of only 0.5 ppm aluminum. The element is widely distributed in plants, where it may be present in significant concentrations, particularly in vegetation in marshy places and acid soils.